You said that 2 will display the same thing, so that means you only need four unique displays, what about the final 1? (9/4= 4 and 1)
A laptop will not be able to do this however, you will need a desktop. I'm not sure if one desktop can have two eyefinity (2x3) displays, but if it does, you only need one computer with two low-end (6450) eyefinity cards, and splitters at the end of those (it is possible that you might need powered splitters).
Your budget for what I posted would be about $3500-$3700. From what I understand, it would be better to purchase the stand separately from the monitors, thereby reducing the cost significantly.